Compositions comprising a neutral surfactant or a reaction product thereof and a reaction product of a saccharide polymer and a fatty acid may be obtained in the presence of water and a hydroxide base (optionally in the presence of the neutral surfactant), the saccharide polymer comprising a dextran, a dextrin compound, or any combination thereof. The reaction product of the saccharide polymer and the fatty acid may be present at a concentration effective to lower surface tension of the neutral surfactant. Depending on the fatty acid identity, among other factors, the compositions may promote emulsification or de-emulsification. In addition, the compositions may promote foam formation under appropriate conditions. Treatment fluids comprising the compositions, including foamed treatment fluids, may be introduced into a subterranean formation to perform a treatment operation in which fluid emulsification or de-emulsification may occur. The reaction products may be incorporated in soaps and other personal care products.